Tony Aldon has another video up in his Inside Emacs series. This one considers the debugging of field formulae in Org tables. If you’ve ever used a formula in an Org table, you’ve probably encountered an error where instead of the field displaying the desired result it shows #ERROR. Usually, it’s a trivial mistake and easy to correct but sometimes the problem isn’t obvious.
Aldon’s video shows how to invoke the formula debugger to resolve those problems. It’s pretty easy; just type Ctrl+c { to toggle the debugger on, rerun the evaluation, and it gives you details of what the evaluator is doing. Take a look at the video to see it in action.
The video goes on to explore various use cases so it’s worth watching to the end. My only complaint is that there’s no audio other than music. I find it hard to follow such videos because my attention is split between the explanatory text and what is happening on the “screen.” It turns out that not everyone agrees so you may not find it a problem. In either case, it’s a good video and worth spending five and half minutes on.